Phosphoric Acid: Dissolution Kinetics of Phosphate Rocks, Precipitation of Dcp and Production of Pure Phosphoric Acid

The production of phosphoric acid by sulfuric acid from high iron content phosphate rocks such as (Abu-Tartur phosphate rocks) has many disadvantages as low quality of produced acid and huge amounts of calcium sulfate. Also traditional process for production of dicalcium phosphate from wet phosphoric acid takes many steps. According to these problems, this work concerned to produce feed grade DCP by direct acidulation of Abu-Tartur phosphate rock with HCl in order to decrease production cost and produce relatively pure phosphoric acid. The leaching of phosphate ore by using dilute HCl was achieved in order to get maximum P2O5 leaching relative to minimum impurities. Kinetic analysis of the data indicates that the leaching process is ash layer diffusion controlled process. The production of DCP from direct acidulate phosphate rock was achieved by precipitating P2O5 by CaCO3. This process has many advantages over the conventional H2SO4 as: decrease production cost. In addition, the production of phosphoric acid from the produced DCP overcomes the traditional production problems and the produced phosphoric acid is more pure than the phosphoric acid produced directly by phosphate ore.